Symmetric Power Functoriality
2026-04-30 14:15 - 16:00 (Europe/Berlin) | Heidelberg
14:15 Talk 2: Background on p-adic Modular Forms: Timo Kränzle

de Rham-Witt complex
2026-05-04 10:15 - 11:45 | Mainz, Hilbertraum (05-432)
Andreas Gieringer:
§3: Dieudonné algebras
More homological algebra and our main examples.
Define Dieudonné algebras (Definition 3.1.2). Discuss Examples 3.1.8, 3.2, and that of the completed de Rham complex as a Dieudonné algebra (Variant 3.3.1, Corollary 3.3.8). Discuss Propositions 3.4.2 and 3.4.3. Prove Propositions 3.5.5 and 3.5.8, and Corollaries 3.5.9 and 3.5.10.

International Seminar on Automorphic Forms
2026-05-05 16:00 - 17:00
Clayton Williams (UIUC): Eisenstein series modulo prime powers
Eisenstein series modulo p are known classically, and recent work of Ahlgren, Hanson, Raum, and Richter determine these series modulo p2. Classical bounds for the weight of a modular form determining an Eisenstein series modulo prime powers pm are roughly pm. I will present joint work with Ahlgren and Castillo showing Eisenstein series are determined modulo pm by a modular form of weight no more than mp, together with an explicit recurrence.
Zoom (680 4828 0736, The password is the first Fourier coefficient of the modular j-function (as digits)).

Specialization of iterated Galois groups
2026-05-06 14:00 - 17:00 | Frankfurt, Robert-Mayer-Str. 6-8, Raum 308
14:00 – 15:15 Talk 1: Leonie Nienhaus (Goethe Universität Frankfurt): Overview of seminar
15:45 – 17:00 Talk 2: Jakob Stix (Goethe Universität Frankfurt): Introduction to arboreal Galois representations

Poincaré-Dualität in Charakteristik p
2026-05-07 09:00 - 11:00 | Heidelberg, Mathematikon, SR 8, Heidelberg, Germany
Vortrag 4: Logarithmische deRham-Witt-Garben III – tba

WKB Analysis: From Quadratic Differentials to Stokes matrices
2026-05-07 10:00 - 12:30 | Frankfurt, Robert-Mayer-Str. 6-8, Raum 309
10:00 – 11:00 Talk 1: Miguel Prado (Goethe Universität): Meromorphic differentials and their trajectories
11:30 – 12:30 Talk 2: Nicole Müller (Goethe Universität): CP1-structures and Schrödinger equations

The K-theory of Z/p^n
2026-05-07 11:15 - 12:45
Talk 4: The Nygaard filtration, syntomic cohomology and the prismatic package –
Marvin Schneider / Rustam Steingart (Universität Heidelberg)

Symmetric Power Functoriality
2026-05-08 09:15 - 11:00 | Heidelberg
09:15 Talk 3 Background on p-adic Hodge Theory: Miriam Philipp

de Rham-Witt Complex
2026-05-11 10:15 - 11:45 | Mainz, Hilbertraum (05-432)
Julie Bannwart
§4: Definition of the complex
The de Rham–Witt complex, its universal property, and relation to the de Rham complex. Cover §3.6 (discuss in particular Lemma 3.6.1 and Proposition 3.6.3). Define the saturated de Rham–Witt complex (Definition 4.1.1, Proposition 4.1.4). State Corollary 4.1.5. Prove Theorem 4.2.4. Prove Theorem 4.3.1 (make sure to state Corollary 4.3.5), and discuss Remark 4.3.6.

International Seminar on Automorphic Forms
2026-05-12 16:00 - 17:00
Martin Raum (Goteborg): The geometric unitary Kudla Conjecture
Kudla and Millson proved that the generating series of cohomology classes associated with special cycles on orthogonal and unitary Shimura varieties is modular. This yields Siegel modular forms and Hermitian modular forms. In later work, Kudla conjectured that the analogous generating series of cycles in the Chow group is modular, too. The orthogonal case of the conjecture was established more than 10 years ago. We resolve the conjecture in the unitary case. In this talk, we explain in particular the role of automatic convergence results in the theory: how they arise and what techniques we currently have to prove them.
Zoom (680 4828 0736, The password is the first Fourier coefficient of the modular j-function (as digits)).

de Rham-Witt complex
2026-05-18 10:15 - 11:45 | Mainz, Hilbertraum (05-432)
Nutsa Gegelia
§5: Extension to schemes
The de Rham–Witt complex as a sheaf. The main goal is to prove Theorem 5.2.2 and Proposition 5.2.4. In pariticular, cover §5.1. As time permits, discuss §5.3 (étale behaviour).

International Seminar on Automorphic Forms
2026-05-19 16:00 - 17:00
Quasimodular forms for the orthogonal group and Gromov-Witten theory
Georg Oberdieck (Heidelberg)
In this talk we begin by introducing quasimodular forms for orthogonal groups as constant terms of almost-holomorphic modular forms. For this we introduce orthogonal lowering and raising operators. Basic results are the description of the spaces of quasimodular forms in terms of vectorvalued modular forms and the interaction with the theta lift. In particular, we give a criterion when the theta lift of a quasimodular form is again quasimodular (it is not always the case). In the second part of the talk I will explain how these quasimodular forms appear in the Gromov-Witten theory of Enriques surfaces. They also want to appear in the Gromov-Witten theory of K3 surfaces, but actually more general automorphic objects there. Based on joint work with Brandon Williams.
Zoom (680 4828 0736, The password is the first Fourier coefficient of the modular j-function (as digits)).

Poincaré-Dualität in Charakteristik p
2026-05-21 09:00 - 11:00 | Heidelberg, Mathematikon, SR 8, Heidelberg, Germany
Vortrag 5: Poincaré-Dualität – Christian Dahlhausen

WKB Analysis: From Quadratic Differentials to Stokes matrices
2026-05-21 10:00 - 12:30 | Frankfurt, Robert-Mayer-Str. 6-8, Raum 309
10:00 – 11:00 Talk 3: Lukas Schneider (Goethe Universität): WKB analysis 1: From Schrödinger equation to the Stokes grap
11:30 – 12:30 Talk 4: Martin Möller (Goethe Universität): WKB analysis 2: Borel summation and summability of the WKB solution

The K-theory of Z/p^n
2026-05-21 11:15 - 12:45
Talk 5: Crystalline degeneration and relative-to-absolute descent I – Anna Blanco Cabanillas (Universität Heidelberg)

Symmetric Power Functoriality
2026-05-21 14:15 - 16:00 | Heidelberg
14:15 Talk 4 Background on Galois Deformation Theory: Mingkuan Zhang

International Seminar on Automorphic Forms
2026-05-26 16:00 - 17:00
Zheng Liu (UCSB): Yoshida lifts and congruences
A Yoshida lift is the theta lift of two modular forms to GSp(4). Its congruence with stable forms on GSp(4) can be used to produce a lower bound on the Selmer group of the Rankin-Selberg product of the two modular forms. We study this congruence by using Rallis inner product formula, Bessel periods and Furusawa’s pullback formula, together with p-adic interpolation.
Zoom (680 4828 0736, The password is the first Fourier coefficient of the modular j-function (as digits)).

Poincaré-Dualität in Charakteristik p
2026-05-28 09:00 - 11:00 | Heidelberg, Mathematikon, SR 8, Heidelberg, Germany
Vortrag 6: Zykelklassenabbildung – Nicolas Otte

WKB Analysis: From Quadratic Differentials to Stokes matrices
2026-05-28 10:00 - 12:30 | Frankfurt, Robert-Mayer-Str. 6-8, Raum 309
10:00 – 11:00 Talk 5: Konstantin Jakob (Goethe Universität): Stokes matrices and Voros periods
11:30 – 12:30 Talk 6: Tianyi Feng (TU Darmstadt): Gentle introduction to the irregular Riemann-Hilbert correspondence

The K-theory of Z/p^n
2026-05-28 11:15 - 12:45 | Heidelberg, Mathematikon, SR 8 and Zoom, INF 205, Heidelberg, Germany
Talk 6: Prismatic envelopes – Otmar Venjakob (Universität Heidelberg)

Symmetric Power Functoriality
2026-05-28 14:15 - 16:00 | Heidelberg
14:15 Talk 5 Deforming (phi,Gamma)-Modules: Benjamin Steklov

de Rham-Witt complex
2026-06-01 10:15 - 11:45 | Mainz, Hilbertraum (05-432)
Timon Tausendpfund
§6: Seminormal aspects
The de Rham–Witt complex is invariant under semi-normalization (and recovers the semi-normalization of a ring). Cover §§6.1-6.2 and §§6.5-6.6, with a focus on Proposition 6.2.1, Corollary 6.5.2, and Theorem 6.5.3. As time permits, introduce crystalline cohomology (as the cohomology of the structure sheaf on the crystalline site relative to the divided power ring (Zp,(p)), see for example the book by Berthelot or Tag 07GI in the Stacks project) and cover §6.4.

International Seminar on Automorphic Forms
2026-06-02 16:00 - 17:00
Spectral theory of automorphic forms: infinite co-volume.
Chris Lutsko (University of Houston)
Given a Lie group G and a discrete subgroup Γ<G, a critical tool used to analyze automorphic forms is to use spectral decomposition (e.g Selberg trace formula). For rank one hyperbolic manifolds the spectrum is either well understood or far beyond reach (e.g Selberg eigenvalue conjecture). In infinite volume the spectrum becomes linked to interesting geometric features of the manifold. In this talk I will survey some results about the spectrum of infinite co-volume subgroups and the connection to geometry and representation theory. This will include work with Dubi Kelmer and Alex Kontorovich, as well as work with Tobias Weich and Lasse Wolf.
Zoom (680 4828 0736, The password is the first Fourier coefficient of the modular j-function (as digits)).

Specialization of iterated Galois groups
2026-06-03 14:00 - 17:00 | Frankfurt, Robert-Mayer-Str. 6-8, Raum 308
14:00 – 15:15 Talk 3: Ruth Wild (Goethe Universität Frankfurt): Extension of the base field – part I
15:45 – 17:00 Talk 4: Magnus Carlson (Goethe Universität Frankfurt): Extension of the base field – part II

de Rham-Witt Complex
2026-06-08 10:15 - 11:45 | Mainz, Hilbertraum (05-432)
Anton Engelmann
Derived considerations
The Nygaard filtration and foundations for the last four talks. Define filtered derived categories (Construction 8.4.1) and the Beilinson t-structure (Remark 8.4.8). Use Proposition 8.4.10 as a definition for the functor Lηp, and give a more explicit description relating it to the functor ηp of §2.1. Discuss Proposition 7.2.4, Theorem 7.4.7 and Corollary 7.4.8. Finally, define the Nygaard filtration as in Proposition 8.4.11. As time permits, come back to some descriptions and properties in §8.1 and §8.2.

International Seminar on Automorphic Forms
2026-06-09 16:00 - 17:00
tba
Hassan Saad (LSU)
Zoom (680 4828 0736, The password is the first Fourier coefficient of the modular j-function (as digits)).

Specialization of iterated Galois groups
2026-06-10 14:00 - 17:00 | Frankfurt, Robert-Mayer-Str. 6-8, Raum 308
14:00 – 15:15 Talk 5: Leonie Nienhaus (Goethe Universität Frankfurt): Proof of theorems 1.2 and 1.3
15:45 – 17:00 Talk 6: Benjamin Steklov (Goethe Universität Frankfurt): Proof of theorem 1.4

Poincaré-Dualität in Charakteristik p
2026-06-11 09:00 - 11:00 | Heidelberg, Mathematikon, SR 8, Heidelberg, Germany
Vortrag 7: Dimension der Kohomologiegruppen – Alexander Schmidt

WKB Analysis: From Quadratic Differentials to Stokes matrices
2026-06-11 10:00 - 12:30 | Frankfurt, Robert-Mayer-Str. 6-8, Raum 309
10:00 – 11:00 Talk 7: Paul Siemon (TU Darmstadt): SL(n, C)-Opers
11:30 – 12:30 Talk 8: Johannes Horn (Goethe Universität): SL(n, C)-spectral networks and WKB analysis for opers

The K-theory of Z/p^n
2026-06-11 11:15 - 12:45 | Heidelberg, Mathematikon, SR 8 and Zoom, INF 205, Heidelberg, Germany
Talk 7: Generators and relations descriptions for the Nygaard filtration –
Otmar Venjakob (Universität Heidelberg)
